Urinary tract infection

Question 1

Is there any indication for culture of urine from bag specimen

Answer 1

No

Question 2

Options for urine culture in children that can void on request and in younger children, septic

Answer 2

Void on request->MSU Younger->clean catch Septic->SPA, catheter urine

Question 3

In a sick child, what to do if positive for UTI and why

Answer 3

Need to still consider other diagnosis, 2% of young children with have asymptomatic bacteruria. Positive dipstick does not rule out possibility of more serious illness.

Question 4

Important history

Answer 4

May have non-specific symptoms: fever, irritability, poor feeding and vomiting Loin/abdominal pain, frequency, dysuria

Question 5

Examination

Answer 5

Usually normal May have fever Supra-pubic/loin pain

Question 6

Acute management- indication for admission, IV antibiotics, gent levels

Answer 6

Indications for admission-

gentamicin and benzylpenicillin

May need fluid resuscitation in shocked infant

Gentamicin levels required prior to third dose.

Consider indications for renal USS investigate full septic screen screen.

Treat with IV antibiotics <6 months.

Consider BC/LP if <1 month

Question 7

Oral antibiotics: type and duration

Answer 7

Infants and Children Trimethoprim 4mg/kg (150mg max) BD (only tablets generally available in community, RCH pharmacy make 10mg/mL suspension for RCH patients) or Trimethoprim and sulphamethoxazole (8mg-40mg per mL) 0.5 ml/kg (20ml max) BD or Cephalexin 15mg/kg (500mg max) TDS –>

10 days total if <2 years, 7 days if >2 years

Question 8

When to consider a renal USS to exclude

Answer 8

Atypical

Not responding after 48 hours

Boys < 3months

>6 months if atypical, >48 hours

Required during admission for UTI

Question 9

Renal USS indicated within 6 weeks and in older children

Answer 9

1. For recurrent

Question 10

Underlying causes of UTI (6)

Answer 10

Obstructed urinary system Vesicoureteric reflux Idiopathic Poor hygeine->kept in wet nappy, wiping back to front in girls Constipation->poor bladder emptying Neurppathic->abnormal spinal function

Question 11

Causes of obstructed urinary system (5)

Answer 11

Pelviureteric obstruction Renal stones Posterior urethral valve Duplex kidney with obstructed poles Horseshoe kidney

Question 12

What xsome abnormality associated with horseshoe kidney

Answer 12

Turner

Question 13

Important history in UTI

Answer 13

Antenatal USS Fever, vomiting, irritability, septic shock, poor feeding, FTT, jaundice, bedwetting, offensive urine, hematuria Poor stream->posterior urethral valves in boys Constipation, deH, spinal disorders FHx renal disease, VU reflux

Question 14

Examination

Answer 14

Fever, perfusion, HR, jaundice Abdominal pain, palpable kidneys Growth BP Spinal abnormalities Genitalia

Question 15

Management of pyelonephritis

Answer 15

Admission 2-4 days IV Oral antibiotics for 10 days following

Question 16

General advice to parents for longer term prevention

Answer 16

Good hygiene Hydration Prompt toileting Avoiding constipation

Question 17

Renal USS- purpose

Answer 17

Anatomical hydronephrosis VUR Renal cortical damage

Question 18

DMSA isotope scan

Answer 18

Inject radioisotope- taken up by renal tubule, quantify differential function between two kidneys and show scarring

Question 19

DTPA renogram

Answer 19

Inject radioisotope, filtered through kidney, shows functional clearance. Cam identify stasis in renal pelvis due to obstruction

Question 20

Micturating urogram

Answer 20

Catheter passed into bladder and contrast injected to detect reflux up into ureters with antibiotic cover

Question 21

Consequences of posterior urethral valves

Answer 21

Bladder hypertrophy bilateral hydronephrosis renal impairment

Question 22

Value of SPA

Answer 22

1. Do not delay antibiotics for sick child
2. Too young for MSU, high probable of UTI, unwell needing more invasive
3. Always send for culture
4. Any growth usually indicates infection

Question 23

Value of catheter specimen

Answer 23

1. Failed SPA
2. SPA still preferred
3. Always send for sulture
4. Any growth >10 ^3 usually indicates infection

Question 24

Value of clean catch

Answer 24

1. Unable to void on request
2. Not too unwell
3. Parents to catch or dish used

Question 25

Value of MSU

Answer 25

1. Can void on request
2. Wash genitalie with water and dry
3. Do not collect first few mls
4. Pure growth >10 ^8 indication of infection

Question 26

Value of full ward test

Answer 26

1. Screening only
2. If UTI suspected need NCS

Question 27

Important points when testing urine

Answer 27

1. Blood and protein are unreliable markers of UTI
2. Not all organisms produce nitrites and nitrites take time to develop in urine and so have poor sensitivity.
3. Not all patients with UTI have pyuria, especially the very young & neutropenic patients. Leucocyte esterase can only be detected with relatively high WBC counts in urine. So the test has low sensitivity.
4. Leucocytes from local sources (vagina, foreskin) may contaminate urine. Leucocytes appear in the urine in many other febrile illnesses eg URTI, pneumonia, meningitis etc. So the specificity is low.